Survey and review of near-field performance assessment

The dissolution rate, or net rate of reaction, of a waste form is limited by one of two processes rate of detachment/dissolution of species from the surface, or rate of transport of dissolved species away from the waste-from surface. Qualitatively, these two cases can be discriminated by a 'flux ratio' defined as the ratio of the rates of surface - reaction control and of transport control. The results indicate that diffusive mass-transfer rate, rather than waste-form reaction rate, is expected to control the release from the EBS. (R.P.) 1 fig